1. Field of the Invention
The present invention relates to a receiving circuit to be used for television receivers and CATV tuners.
2. Description of the Prior Art
In recent years, with the adoption of multi-channel CATV, wide band receiving has been necessitated. An example of tuners for such wide band receiving is shown in "Wide Band Multi-channel Tuner", Sato, et al., ITEJ (the Institute of Television Engineers of Japan) Technical Report, RE86-6, Feb. 27, 1986. In the said tuner, two or more filters are changed over with a filter selection switch to limit the number of channels to be inputted into the amplifier circuit or mixer circuit, and gain control is effected with an attenuator after the filter selection switch. According to the above construction, however, when the gain of the tuner is the maximum, the noise figure is deteriorated by insertion losses caused by the filter selection switch and the attenuator.